scholarly journals Modification of Microstructure and Texture in Highly Non-Flammable Mg-Al-Zn-Y-Ca Alloy Sheets by Controlled Thermomechanical Processes

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 181 ◽  
Author(s):  
Sangbong Yi ◽  
José Victoria-Hernández ◽  
Young Kim ◽  
Dietmar Letzig ◽  
Bong You
Keyword(s):  
Mechanical Properties ◽  
Transverse Direction ◽  
Texture Evolution ◽  
Rolling Direction ◽  
Reduction Degree ◽  
Rolling Schedule ◽  
Texture Type ◽  
Basal Pole ◽  
Thermomechanical Processes ◽  
Basal Type

The influence of rolling temperature and pass reduction degree on microstructure and texture evolution was investigated using an AZXW3100 alloy, Mg-3Al-1Zn-0.5Ca-0.5Y, in wt.%. The change in the rolling schedule had a significant influence on the resulting texture and microstructure from the rolling and subsequent annealing. A relatively strong basal-type texture with a basal pole split into the rolling direction was formed by rolling at 450 °C with a decreasing scheme of the pass reduction degrees with a rolling step, while the tilted basal poles in the transverse direction were developed by using an increasing scheme of the pass reduction degrees. Rolling at 500 °C results in a further distinct texture type with a far more largely tilted basal pole into the rolling direction. The directional anisotropy of the mechanical properties in the annealed sheets was caused by the texture and microstructural features, which were in turn influenced by the rolling condition. The Erichsen index of the sheets varied in accordance to the texture sharpness, i.e., the weaker the texture the higher the formability. The sheet with a tetrarchy distribution of the basal poles into the transverse and rolling directions shows an excellent formability with an average Erichsen index of 8.1.

scholarly journals The Edge Crack, Texture Evolution, and Mechanical Properties of Mg-1Al-1Sn-Mn Alloy Sheets Prepared Using On-Line Heating Rolling

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 860 ◽  
Author(s):  
Qiang Liu ◽  
Jiangfeng Song ◽  
Fusheng Pan ◽  
Jia She ◽  
Shuo Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
Rolling Direction ◽  
Rolling Temperature ◽  
Line Heating ◽  
Basal Pole ◽  
On Line ◽  
Edge Cracks ◽  
Conventional Rolling

A series of Mg-1Al-1Sn-Mn magnesium alloy sheets were rolled from 3 mm to 1 mm under temperatures of 150 °C, 200 °C, and 250 °C in four rolling passes using on-line heating rolling. The conventional rolling was also performed for comparison. Scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) technologies were utilized to characterize the edge cracks as well as the microstructure of rolled thin sheets. The result revealed that the number of edge cracks decreased dramatically with the increase of rolling temperature. No visible edge cracks were found on the surface of sheets rolled at 250 °C by on-line heating rolling, while the conventional rolling at the same temperature still resulted in severe edge cracks. The intensity of the basal texture for on-line rolled sheets increased from 4.982 to 9.596 as the rolling temperature increased from 150 °C to 250 °C, which was related to the reorientation of new grains and deformation grains remained after rolling. The direction of the basal pole slightly tilted towards the rolling direction (RD), which may be mainly attributed to the activation of a pyramidal slip, as well as the tension imposed on the samples. Moreover, mechanical properties were improved after rolling on the basis of the strong texture and grain refinement. The highest yield strength (YS), ultimate tensile strength (UTS), and the maximum elongation of the rolled sheets were 148 MPa, 298 MPa, and 14.6% along the RD, respectively.

Rolling Temperature and Subsequent Annealing on Microstructure, Texture and Mechanical Properties of Consecutive Rolled Mg-2.0Zn-0.8Gd Alloy

2013 ◽  
Vol 747-748 ◽  
pp. 369-376 ◽  
Author(s):  
Hong Yan ◽  
Rong Shi Chen ◽  
En Hou Han
Keyword(s):  
Mechanical Properties ◽  
Dynamic Recrystallization ◽  
Transverse Direction ◽  
Rolling Direction ◽  
Annealing Process ◽  
Normal Direction ◽  
Rolling Temperature ◽  
Rolled Sheet ◽  
Basal Texture ◽  
Different Temperatures

Mg-2.0Zn-0.8Gd (wt. %) alloy was rolled consecutively at different temperatures. The influence of rolling temperature and annealing process on the microstructure, texture and mechanical properties of the sheet were investigated. A deformation microstructure consisting of many intersected twins and a few dynamic recrystallization grains, and a basal texture with basal poles tilting about ± 10-15° from the normal direction towards the rolling direction were observed in the as-rolled sheet after 4 consecutive rolling processes. Static recrystallizaiton took place in the sheet after annealed above 300 °C. The annealed sheet exhibited a uniform microstructure and a non-basal texture with basal poles tilting about ± 38-43° from the normal direction towards the transverse direction. The annealed sheets exhibited higher ductility about 32% along the rolling direction and 40% along the transverse direction comparing with the as-rolled sheets. The static recrystallization during annealing process was helpful to modify the texture as well as the dynamic recrystallization during rolling in the RE-containing alloys.

Effects of Cross-Rolling on Deformation Texture Evolution in Unalloyed Titanium

2016 ◽  
Vol 879 ◽  
pp. 2014-2019
Author(s):  
Osamu Umezawa ◽  
Norimitsu Koga
Keyword(s):  
Rolling Mill ◽  
Transverse Direction ◽  
Texture Evolution ◽  
True Strain ◽  
Rolling Direction ◽  
Deformation Texture ◽  
Fiber Texture ◽  
Cross Rolling ◽  
Flat Rolling ◽  
The Cross

Unalloyed titanium was rolled with 20% reduction in each pass at 293 K using a cross rolling mill, where the upper and lower rolling axes were skewed each other at an angle of 0, 5 or 10 degree with parallel position. Multi-pass flat-rolling was carried out without any lubricants up to the true strain of 1, where two kinds of rolling directions such as tandem (uni-direction for all passes) and reverse (opposite direction in every passes) were adopted. The strain of specimens was increased proportionally as higher passes regardless of the rolling conditions. The transverse direction (TD) split deformation texture in titanium was generally developed under the cross angle of 0 degree. In the present strips of tandem, a main orientation was identified as (-12-18)[10-10]. In the case of tandem with the cross angle of 5 degree, a fiber texture was developed along (-12-18). That is the reason why a rotation in the rolling direction (RD) was overlapped. In the case of reverse with the cross angle of 5 degree, the main orientation was separated into [10-10] and [2-311] that were corresponded to TD and RD splits, respectively.

scholarly journals Microstructural Evolution during Recrystallization of Magnesiun Alloys

2012 ◽  
Vol 706-709 ◽  
pp. 1291-1296 ◽  
Author(s):  
Sang Bong Yi ◽  
Jan Bohlen ◽  
Stefanie Sandlöbes ◽  
Stefan Zaefferer ◽  
Dietmar Letzig ◽  
...  
Keyword(s):  
Grain Growth ◽  
Microstructural Evolution ◽  
Shear Bands ◽  
Rolling Direction ◽  
Sheet Rolling ◽  
Significant Difference ◽  
Basal Pole ◽  
Cold Rolled ◽  
Basal Type ◽  
Weak Texture

Microstructural evolution during the annealing of cold rolled Mg, Mg-1.5Nd and Mg-3Y sheets has been examined. The experimental results show a significant difference in recrystallization kinetics and grain growth between pure Mg and Mg-RE alloy sheets. Pure Mg sheet shows rapid recrystallization and grain growth, whereas recrystallization is considerably retarded in the Mg-RE alloys. Although recrystallized grains which are triggered at shear bands in the cold rolled pure Mg sheet show a relatively weak texture with a basal pole split into the sheet rolling direction, rapid grain growth is accompanied by re-strengthening of the basal-type texture. In contrast, a weak texture appears in the early recrystallization stage in Mg-RE alloys and is retained during annealing due to retarded recrystallization and grain growth.

scholarly journals Microstructure, Texture and Mechanical Properties of AZ31 Magnesium Alloy Fabricated by High Strain Rate Biaxial Forging

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3050 ◽  
Author(s):  
Yuanzhi Wu ◽  
Jizhao Liu ◽  
Bin Deng ◽  
Tuo Ye ◽  
Qingfen Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Rolling Direction ◽  
Rolling Texture ◽  
Az31 Magnesium Alloy ◽  
Accumulated Strain ◽  
Basal Pole

High strain rate biaxial forging (HSRBF) was performed on AZ31 magnesium alloy to an accumulated strain of ΣΔε = 1.32, the related microstructure, texture and mechanical properties were investigated. It was found that the microstructure evolution can be divided into two steps during HSRBF. In the early forging processes, the refinement of the grain is obvious, the size of ~10 μm can be achieved; this can be attributed to the unique mechanisms including the formation of high density twins ({1012} extension twin and {1011}-{1012} secondary twin) and subsequently twining induced DRX (dynamic recrystallization). The thermal activated temperature increases with the increase of accumulated strain and results in the grain growth. Rolling texture is the main texture in the high strain rate biaxial forged (HSRBFed) alloys, the intensity of which decreases with the accumulated strain. Moreover, the basal pole rotates towards the direction of forging direction (FD) after each forging pass, and a basal texture with basal pole inclining at 15–20° from the rolling direction (RD) is formed in the full recrystallized HSRBFed alloys. The grain refinement and tiled texture are attributed to the excellent strength and ductility of HSRMBFed alloys with full recrystallized structure. As the accumulated strain is ΣΔε = 0.88, the HSRMBFed alloy displays an outstanding combination of mechanical properties, the ultimate tensile strength (UTS) is 331.2 MPa and the elongation is 25.1%.

scholarly journals Effect of Al Content on Texture Evolution and Recrystallization Behavior of Non-Flammable Magnesium Sheet Alloys

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 468
Author(s):  
Sumi Jo ◽  
Dietmar Letzig ◽  
Sangbong Yi
Keyword(s):  
Transverse Direction ◽  
Texture Evolution ◽  
Rolling Direction ◽  
Alloy Sheet ◽  
Alloying Elements ◽  
Grain Structure ◽  
Recrystallization Behavior ◽  
Al Content ◽  
Split Component ◽  
The Matrix

The effect of Al content on the texture evolution and recrystallization behavior of the non-flammable Mg sheet alloys containing Ca and Y was investigated in this study. With a decrease in the Al content from 3 wt.% to 1 wt.%, the amounts of the other alloying elements dissolved in the matrix, especially Ca, are increased. The increase of the alloying elements in a solid solution brought out the retarded recrystallization and weakened texture with the basal poles tilted toward the sheet transverse direction. Extension twinning activity increased when Al content with decreasing, resulting in the texture broadening towards the sheet transverse direction in the as-rolled sheets. The textures of the AZXW1000 and AZXW2000 sheets weaken uniformly in all sample directions during annealing, while the AZXW3000 sheet shows less weakening of the rolling direction split component. The texture weakening of the alloys with lower Al contents is attributed to the retarded recrystallization caused by the larger amount of the dissolved Ca solutes. Based on the non-basal texture and relatively stable grain structure, the Mg alloy sheet containing a relatively small amount of Al is advantageous to improve the formability.

scholarly journals Evolution of Microstructure and Mechanical Properties of Mg-6Al Alloy Processed by Differential Speed Rolling upon Post-Annealing Treatment

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 926
Author(s):  
Honglin Zhang ◽  
Zhigang Xu ◽  
Sergey Yarmolenko ◽  
Laszlo J. Kecskes ◽  
Jagannathan Sankar
Keyword(s):  
Mechanical Properties ◽  
Annealing Temperature ◽  
Mechanical Response ◽  
Rolling Direction ◽  
Rolled Plate ◽  
Speed Ratio ◽  
Roll Temperature ◽  
Basal Pole ◽  
Differential Speed Rolling ◽  
Differential Speed

Magnesium-6 wt.% aluminum (Mg-6Al) alloy plates with a 6-millimeter thickness were processed from an initial 12-millimeter thickness by differential speed rolling (DSR), with a 0.76-millimeter thickness reduction per pass using a speed ratio of 2, preheating temperature of 315 °C, and roll temperature of 265 °C. The effects of annealing temperature of 250, 275, and 300 °C with a corresponding holding time of 15 min on the microstructure, texture, and mechanical properties were investigated. Key results show that dynamic recrystallization (DRX) occurred during the roll processing, resulting in a greatly reduced grain size. In addition, the basal pole of the as-rolled plate was inclined to the rolling direction (RD) by ~20°, due to the shear strain introduced during DSR. Subsequent annealing caused grain growth, eliminated the basal pole inclination towards the RD, and slightly increased the pole intensity. Compared with the as-rolled plate, the average of the ultimate tensile strength (UTS) and the yield strength (YS) of the annealed plates decreased, while the average elongation at fracture (εf) increased. With the annealing temperature of 275 °C, the plate achieved a good combination of mechanical properties with UTS, YS, and εf being 292.1 MPa, 185.0 MPa, and 24.9%, respectively. These results suggest that post-roll annealing is an effective way to improve the mechanical response of this Mg alloy processed by DSR.

scholarly journals Directionally-Dependent Mechanical Properties of Ti6Al4V Manufactured by Electron Beam Melting (EBM) and Selective Laser Melting (SLM)

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3603
Author(s):  
Tim Pasang ◽  
Benny Tavlovich ◽  
Omry Yannay ◽  
Ben Jakson ◽  
Mike Fry ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Tensile Strength ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Electron Beam Melting ◽  
Rolling Direction ◽  
Laser Melting ◽  
Plate Rolling

An investigation of mechanical properties of Ti6Al4V produced by additive manufacturing (AM) in the as-printed condition have been conducted and compared with wrought alloys. The AM samples were built by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) in 0°, 45° and 90°—relative to horizontal direction. Similarly, the wrought samples were also cut and tested in the same directions relative to the plate rolling direction. The microstructures of the samples were significantly different on all samples. α′ martensite was observed on the SLM, acicular α on EBM and combination of both on the wrought alloy. EBM samples had higher surface roughness (Ra) compared with both SLM and wrought alloy. SLM samples were comparatively harder than wrought alloy and EBM. Tensile strength of the wrought alloy was higher in all directions except for 45°, where SLM samples showed higher strength than both EBM and wrought alloy on that direction. The ductility of the wrought alloy was consistently higher than both SLM and EBM indicated by clear necking feature on the wrought alloy samples. Dimples were observed on all fracture surfaces.

scholarly journals Microstructural Influence on Stretch Flangeability of Ferrite–Martensite Dual-Phase Steels

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1022
Author(s):  
Jae Hyung Kim ◽  
Taekyung Lee ◽  
Chong Soo Lee
Keyword(s):  
Mechanical Strength ◽  
Uniform Distribution ◽  
Transverse Direction ◽  
Rolling Direction ◽  
Expansion Ratio ◽  
Dual Phase ◽  
Normal Anisotropy ◽  
Hole Expansion Ratio ◽  
Dp Steels ◽  
Microstructural Effect

This work investigated the microstructural effect on stretch flangeability of ferrite–martensite dual-phase (DP) steels. Three types of DP steels with various martensitic structures were prepared for the research: fibrous martensite in water-quenched (WQ) sample, chained martensite in air-quenched (AQ) sample, and coarse martensite in step-quenched (SQ) sample. The WQ specimen exhibited the highest mechanical strength and hole expansion ratio compared to the AQ and SQ samples despite their similar fraction of martensite. Such a result was explained in view of uniform distribution of fine martensite and high density of geometrically necessary dislocations in the WQ specimen. Meanwhile, most cracks initiated at either rolling or transverse direction during the stretch flangeability test regardless of the martensitic morphology. It was attributed to the highest average normal anisotropy in the direction of 45° to rolling direction.

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